I want to learn the fundamentals of fighting games. Street Fighter has always seen like the most basic one with skills that can translate to other fighting games.

I want to get into the most basic fighting game, Street Fighter has always given me the impression of being the most simple one with characters like Ryu. Not talking about so simple that is easy, but so simple that you will get punished for basic mistakes of the player. Something like Annie in League of Legends.

What is the cheapest option to get into fighting games? It has to include online rank since I won't be playing local.

I am willing to buy SF5, but the reviews on Steam are mixed. If I can play Ryu (best character to learn the game?), then I don't care anything else as long as I can play with the rest of the playerbase (not needing every character to play against all of them).

Or should I go to Ultra Street Fight IV? Is the playerbase good?